Developed for the Office of Naval Research in 2009, this vehicle was designed to conduct ocean underwater surveillance, enabling it potentially to detect chemical spills, monitor the presence of ships and submarines, and observe the migration of schools of fish.
Recently, a team at VirginiaTech has improved the performance of this silicone swimmer, enabling it to better overcome the limitations of its artificial skin and better mimic the true motion of a jellyfish. Details on this new design and how it might provide new insights into jellyfish propulsion mechanisms will be presented at the 2011 meeting of the American Physical Society’s Division of Fluid Dynamics in Baltimore, Md., Nov. 20-22.
According to VirginiaTech mechanical engineer Alex Villanueva, Robojelly looks very similar to an actual jellyfish. “Its geometry is copied almost exactly from a moon jellyfish [Aurelia aurita],” he said. The robot is built out of silicone and uses shape memory alloy (SMA) actuators to swim.
To move through the water, the natural animal uses the bell section of its body, which deforms and contracts to provide thrust. The lower, or lagging, section of the bell is known as the flexible margin, and it deforms slightly later in the swimming process than the rest of the bell. Until recently, however, Robojelly lacked this crucial piece of anatomy in its design.
Villanueva and his colleagues tested a number of different designs for their robot, some with and without an analog to a flexible margin. Initially, the artificial materials used in construction presented a problem. Unlike their natural counterparts, the artificial materials tended to fold as they deformed, reducing Robojelly’s performance. After testing a number of designs and lengths for the folding margin, the engineers discovered that cutting slots into the bell reduced this unwanted folding effect.
This gave Robojelly a truer swimming stroke, as well as a big boost in speed.
“These results clearly demonstrate that the flap plays an important role in the propulsion mechanism of Robojelly and provides an anatomical understanding of natural jellyfish,” said Villanuerva.
The talk, “Effects of a flexible margin on Robojelly vortex structures,” is at 3:05 p.m. on Tuesday, Nov. 22, 2011, in Room 324. Abstract: http://absimage.aps.org/image/MWS_DFD11-2011-001706.pdfMORE MEETING INFORMATION
Charles Blue | Newswise Science News
36 big data research projects
21.02.2017 | Schweizerischer Nationalfonds SNF
Coastal wetlands excel at storing carbon
01.02.2017 | University of Maryland
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
20.02.2017 | Materials Sciences
20.02.2017 | Health and Medicine
20.02.2017 | Health and Medicine